/*
 * Copyright 2002-2019 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.core.io.buffer;

import org.springframework.util.Assert;

import java.io.InputStream;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;
import java.util.function.IntPredicate;

/**
 * DataBuffer implementation created by {@link LeakAwareDataBufferFactory}.
 *
 * @author Arjen Poutsma
 */
class LeakAwareDataBuffer implements PooledDataBuffer {

    private final DataBuffer delegate;

    private final AssertionError leakError;

    private final LeakAwareDataBufferFactory dataBufferFactory;


    LeakAwareDataBuffer(DataBuffer delegate, LeakAwareDataBufferFactory dataBufferFactory) {
        Assert.notNull(delegate, "Delegate must not be null");
        Assert.notNull(dataBufferFactory, "DataBufferFactory must not be null");
        this.delegate = delegate;
        this.dataBufferFactory = dataBufferFactory;
        this.leakError = createLeakError(delegate);
    }

    private static AssertionError createLeakError(DataBuffer delegate) {
        String message = String.format("DataBuffer leak detected: {%s} has not been released.%n" +
                        "Stack trace of buffer allocation statement follows:",
                delegate);
        AssertionError result = new AssertionError(message);
        // remove first four irrelevant stack trace elements
        StackTraceElement[] oldTrace = result.getStackTrace();
        StackTraceElement[] newTrace = new StackTraceElement[oldTrace.length - 4];
        System.arraycopy(oldTrace, 4, newTrace, 0, oldTrace.length - 4);
        result.setStackTrace(newTrace);
        return result;
    }

    AssertionError leakError() {
        return this.leakError;
    }


    public DataBuffer getDelegate() {
        return this.delegate;
    }

    @Override
    public boolean isAllocated() {
        return this.delegate instanceof PooledDataBuffer &&
                ((PooledDataBuffer) this.delegate).isAllocated();
    }

    @Override
    public PooledDataBuffer retain() {
        if (this.delegate instanceof PooledDataBuffer) {
            ((PooledDataBuffer) this.delegate).retain();
        }
        return this;
    }

    @Override
    public boolean release() {
        if (this.delegate instanceof PooledDataBuffer) {
            ((PooledDataBuffer) this.delegate).release();
        }
        return isAllocated();
    }

    // delegation


    @Override
    public LeakAwareDataBufferFactory factory() {
        return this.dataBufferFactory;
    }

    @Override
    public int indexOf(IntPredicate predicate, int fromIndex) {
        return this.delegate.indexOf(predicate, fromIndex);
    }

    @Override
    public int lastIndexOf(IntPredicate predicate, int fromIndex) {
        return this.delegate.lastIndexOf(predicate, fromIndex);
    }

    @Override
    public int readableByteCount() {
        return this.delegate.readableByteCount();
    }

    @Override
    public int writableByteCount() {
        return this.delegate.writableByteCount();
    }

    @Override
    public int readPosition() {
        return this.delegate.readPosition();
    }

    @Override
    public DataBuffer readPosition(int readPosition) {
        return this.delegate.readPosition(readPosition);
    }

    @Override
    public int writePosition() {
        return this.delegate.writePosition();
    }

    @Override
    public DataBuffer writePosition(int writePosition) {
        return this.delegate.writePosition(writePosition);
    }

    @Override
    public int capacity() {
        return this.delegate.capacity();
    }

    @Override
    public DataBuffer capacity(int newCapacity) {
        return this.delegate.capacity(newCapacity);
    }

    @Override
    public DataBuffer ensureCapacity(int capacity) {
        return this.delegate.ensureCapacity(capacity);
    }

    @Override
    public byte getByte(int index) {
        return this.delegate.getByte(index);
    }

    @Override
    public byte read() {
        return this.delegate.read();
    }

    @Override
    public DataBuffer read(byte[] destination) {
        return this.delegate.read(destination);
    }

    @Override
    public DataBuffer read(byte[] destination, int offset, int length) {
        return this.delegate.read(destination, offset, length);
    }

    @Override
    public DataBuffer write(byte b) {
        return this.delegate.write(b);
    }

    @Override
    public DataBuffer write(byte[] source) {
        return this.delegate.write(source);
    }

    @Override
    public DataBuffer write(byte[] source, int offset, int length) {
        return this.delegate.write(source, offset, length);
    }

    @Override
    public DataBuffer write(DataBuffer... buffers) {
        return this.delegate.write(buffers);
    }

    @Override
    public DataBuffer write(ByteBuffer... buffers) {
        return this.delegate.write(buffers);
    }

    @Override
    public DataBuffer write(CharSequence charSequence, Charset charset) {
        return this.delegate.write(charSequence, charset);
    }

    @Override
    public DataBuffer slice(int index, int length) {
        return this.delegate.slice(index, length);
    }

    @Override
    public ByteBuffer asByteBuffer() {
        return this.delegate.asByteBuffer();
    }

    @Override
    public ByteBuffer asByteBuffer(int index, int length) {
        return this.delegate.asByteBuffer(index, length);
    }

    @Override
    public InputStream asInputStream() {
        return this.delegate.asInputStream();
    }

    @Override
    public InputStream asInputStream(boolean releaseOnClose) {
        return this.delegate.asInputStream(releaseOnClose);
    }

    @Override
    public OutputStream asOutputStream() {
        return this.delegate.asOutputStream();
    }

    @Override
    public boolean equals(Object o) {
        if (o instanceof LeakAwareDataBuffer) {
            LeakAwareDataBuffer other = (LeakAwareDataBuffer) o;
            return this.delegate.equals(other.delegate);
        }
        else {
            return false;
        }
    }

    @Override
    public int hashCode() {
        return this.delegate.hashCode();
    }

    @Override
    public String toString() {
        return String.format("LeakAwareDataBuffer (%s)", this.delegate);
    }
}
